C0845
DTC C0845
Circuit Description
The body control module (BCM) contains the 2-amp EPS fuse. This fuse and the ignition 1 voltage circuit supply ignition voltage to the power steering control module (PSCM). This ignition voltage is used to wake up the PSCM. The PSCM receives a class 2 power moding message from the BCM to determine the position of the ignition switch. When a power mode message is received, the PSCM monitors the ignition 1 voltage circuit to detect if a short to voltage, short to ground, or an open exists.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC C0845 Device Ignition 1 Circuit
This vehicle has DTCs which include DTC Symptoms. For more information on DTC Symptoms, refer to DTC Symptom Description.
Conditions for Running the DTC
The PSCM has 9-16 volts.
Conditions for Setting the DTC
^ The class 2 power mode message indicates OFF, and the ignition 1 voltage circuit is shorted to voltage.
^ The class 2 power mode message indicates ON, and the ignition 1 voltage circuit is shorted to ground or open.
^ DTCs U1300 and U1301 are not set.
Action Taken When the DTC Sets
^ DTC C0847 is stored in memory.
^ The instrument panel cluster (IPC) message center displays the PWR STR warning message.
^ The EPS system is disabled.
Conditions for Clearing the DTC
^ A current DTC will clear when the malfunction is no longer present.
^ A history DTC will clear after 100 consecutive malfunction-free ignition cycles.
^ Using a scan tool
Diagnostic Aids
The ignition 1 voltage circuit supplies several other control modules with ignition voltage. Before preceding with the diagnostic table below, ensure no other control modules that use the ignition 1 circuit for their ignition voltage supply have any ignition voltage malfunctions present, such as the sensing and diagnostic module (SDM) or the cruise control module (CCM). Refer to Power Distribution Schematics. If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections for further diagnosis. Component Tests and General Diagnostics
Test Description
The numbers below refer to the step numbers on the diagnostic table.
2. This step tests if the malfunction is intermittent.
5. This step tests if a short to ground exists in the ignition 1 voltage circuit, or in the PSCM.
